Daily energy expenditure of Florida Scrub-Jays (Aphelocoma coerulescens) in suburban and wildland landscapes

Urbanization alters ecological systems, disturbance regimes, food webs, and a variety of other processes that can influence local flora and fauna. In birds, most studies have focused on behavioral or demographic responses to altered conditions; however, the physiological mechanisms associated with these responses have been understudied. We have previously documented shifts in foraging behavior because of the availability of human-provided food; we sought to see if this was driven by or associated with a change in field metabolic rates. We measured field metabolic rates (FMR), a measure of daily energy expenditure (DEE), of Florida Scrub-Jays (Aphelocoma coerulescens) in 2 habitats using doubly labeled water (DLW). One population of jays lived in wildland habitat, the other in a suburban area where the habitat was badly degraded. During the breeding season FMR of suburban males exceeded that of wildland males by over 100%. Female FMR did not differ between sites but increased following incubation. In the wildlands, FMRs of females were barely lower than those of males, but in the suburban landscape, female FMRs were much lower than in males. For both sexes in the wildlands, FMRs were about 3.53 basal rates of metabolism (BMR) during breeding; in the suburbs female FMR exceeded BMR by 43 but did not differ from that of wildland females. Suburban male FMRs exceeded BMR by 7.13. During the nonbreeding seasons of fall and winter, FMR did not differ between habitats, ranging from 1.73 to 2.13 BMR, thus it is the breeding season that separated wildland and suburban jays energetically. In both habitats, a low water economy index (mL/kJ) and low water fluxes indicated that these jays are well adapted to their xeric habitat, but their FMRs distinguished them from desert birds. The very high energetic cost associated with breeding for suburban males may help explain why in the metapopulation of Florida Scrub-Jays, suburban jay populations are sinks. This study underscores the value of physiology in the conservation of listed species

Does optimal foraging theory explain why suburban Florida scrub-jays ( Aphelocoma coerulescens ) feed their young human-provided food?

Optimal foraging theory assumes that a forager can adequately assess the quality of its prey and predicts that parents feed their young low-quality foods only when suffering unpredicted reductions in their ability to provision. Wildland Florida scrub-jays feed their young exclusively arthropods, but suburban parents include human-provided foods in the nestling diet, with possible costs in terms of reduced growth and survival. We tested experimentally whether parents feed human-provided foods, given the apparent costs, because: 1) they do not discriminate between food types, 2) they switch to low-quality, abundant foods when natural food availability in the environment is low, or 3) they switch when the time needed to obtain natural food is high. Parents discriminated between natural and human-provided foods by showing a preference for natural foods when rearing young. When the handling time of natural foods was increased experimentally, parents in the suburban and wildland habitats switched to human-provided foods. Supplementation with natural foods increased preference for this food in both habitats. Suburban parents chose more natural foods than wildland parents, suggesting that they have a greater preference for natural foods. Regardless of preferences demonstrated at feeders, parents in both the suburbs and wildlands delivered mostly natural foods to nestlings, independent of natural food availability. Nonetheless, natural foods are likely to be scarcer in the environment than in our experimental tests. Because natural food availability is lower in the suburbs than in the wildland habitat, parents in the suburbs may be forced to switch to human-provided foods when feeding nestling

Mass fluctuation in breeding females, males, and helpers of the Florida scrub-jay Aphelocoma coerulescens

Much evidence suggests that birds actively regulate their body mass reserves relative to their energy needs. Energy requirements during reproduction may differ in relation to sex-specific behavioural roles or, in the case of cooperative breeders, breeders relative to helpers. We measured body mass of free-living Florida scrub-jays throughout the nesting season by training them to land on an electronic balance. Jays exhibited a pattern of diurnal linear mass gain, from morning to afternoon. Day-to-day mass fluctuations, defined as the difference between mass on two consecutive days, were small (>80% were within 2 g, less than 3% of the mass of an adult bird) for all classes of jays: female breeders, male breeders and prebreeding helpers. The jays, which live in subtropical south-central Florida, did not exhibit changes in day-to-day mass fluctuation relative to weather or climate variables or calendar date. Day-to-day mass fluctuations influenced mass fluctuation between the following third and fourth days. These changes were usually compensatory, indicating that jays are able to regulate their body mass on a short-term basis, despite strong differences in their roles in reproduction. During reproduction, jays have a relatively predictable and abundant food supply, thus the appropriate strategy may be to maintain a stable body mass that balances some energy reserves against maintaining a low body mass for efficient flight, as required during reproduction

S21RS SGR No. 5 (Mardi Gras Break)

A Resolution To Urge and Request LSU Faculty to provide leisure on February 15th (the Monday before Mardi Gras) by either not counting attendance, no graded in class assignments, or no class if possible

Nurses\u27 Alumnae Association Bulletin, June 1970

Alumnae President\u27s Message Congratulations Alumni Association Portrait of Samuel D. Gross Officers and Chairmen of Committees Financial Report Progress of Jefferson 1969-1970 School of Nursing Annual Report School of Practical Nursing Report Emergency Department Patient Services Department Annual Luncheon Pictures Committee Reports Progress of the Alumnae Association Crossword Puzzle Missing Graduates Resume of Alumnae Meetings Minutes Class News Student Nurses Section Crossword Puzzle Answers Notice

Probing the first galaxies with the SKA

Observations of anisotropies in the brightness temperature of the 21 cm line of neutral hydrogen from the period before reionization would shed light on the dawn of the first stars and galaxies. In this paper, we use large-scale semi-numerical simulations to analyse the imprint on the 21 cm signal of spatial fluctuations in the Lyman-alpha flux arising from the clustering of the first galaxies. We show that an experiment such as the Square Kilometer Array (SKA) can probe this signal at the onset of reionization, giving us important information about the UV emission spectra of the first stars and characterizing their host galaxies. SKA-pathfinders with ~ 10% of the full collecting area should be capable of making a statistical detection of the 21 cm power spectrum at redshifts z 67 MHz). We then show that the SKA should be able to measure the three dimensional power spectrum as a function of the angle with the line of sight and discuss the use of the redshift space distortions as a way to separate out the different components of the 21 cm power spectrum. We demonstrate that, at least on large scales where the Lyman-alpha fluctuations are linear, they can be used as a model independent way to extract the power spectra due to these Lyman-alpha fluctuations.Comment: 13 pages, 17 figures. New version to match version accepted by A&A. Improved discussions on the Lyman-alpha simulation, adiabatic cooling fluctuations, the Fisher matrix approach and the Poisson term calculation. New version of the code available at: http://www.SimFast21.or

BRCA1 haploinsufficiency for replication stress suppression in primary cells

BRCA1—a breast and ovarian cancer suppressor gene—promotes genome integrity. To study the functionality of BRCA1 in the heterozygous state, we established a collection of primary human BRCA1+/+ and BRCA1mut/+ mammary epithelial cells and fibroblasts. Here we report that all BRCA1mut/+ cells exhibited multiple normal BRCA1 functions, including the support of homologous recombination- type double-strand break repair (HR-DSBR), checkpoint functions, centrosome number control, spindle pole formation, Slug expression and satellite RNA suppression. In contrast, the same cells were defective in stalled replication fork repair and/or suppression of fork collapse, that is, replication stress. These defects were rescued by reconstituting BRCA1mut/+ cells with wt BRCA1. In addition, we observed ‘conditional’ haploinsufficiency for HR-DSBR in BRCA1mut/+ cells in the face of replication stress. Given the importance of replication stress in epithelial cancer development and of an HR defect in breast cancer pathogenesis, both defects are candidate contributors to tumorigenesis in BRCA1-deficient mammary tissue

Dynamic capabilities and knowledge management: an integrative role for learning?

Modern strategic management theories try to explain why firms differ, because new sources of competitive advantage are keenly sought in the dynamic and complex environment of global competition. Two areas in particular have attracted the attention of researchers: the role of dynamic capabilities, and the firm's abilities for knowledge management. In this paper, we argue that there is a link between these two concepts, which has not been fully articulated in the literature. The aim of the paper is therefore to ascertain the conceptual connection between them as a basis for future research. Our proposed framework acknowledges and critiques the distinct roots of each field, identifies boundaries, and proposes relationships between the constructs and firm performance

Rational design of glycomimetic compounds targeting the Saccharomyces cerevisiae transglycosylase Gas2

The transglycosylase Saccharomyces cerevisiae Gas2 (ScGas2) belongs to a large family of enzymes that are key players in yeast cell wall remodeling. Despite its biological importance, no studies on the synthesis of substrate-based compounds as potential inhibitors have been reported. We have synthesized a series of docking-guided glycomimetics that were evaluated by fluorescence spectroscopy and saturation-transfer difference (STD) NMR experiments, revealing that a minimum of three glucose units linked via a β-(1,3) linkage are required for achieving molecular recognition at the binding donor site. The binding mode of our compounds is further supported by STD-NMR experiments using the active site-mutants Y107Q and Y244Q. Our results are important for both understanding of ScGas2-substrate interactions and setting up the basis for future design of glycomimetics as new antifungal agents.This study was supported by the Ministerio de Economía y Competitividad (MINECO) and FEDER Program (Madrid, Spain, projects CTQ2013-44367-C2-1-P and CTQ2013-44367-C2-2-P), and the Gobierno de Aragón (Zaragoza, Spain. E. M. and J. V.G. thank MEC for FPU and FPI predoctoral grants, respectively. The ARAID Foundation (Gobierno de Aragón, Spain) is also acknowledged for financial support.Peer reviewe

Canine respiratory coronavirus employs caveolin-1-mediated pathway for internalization to HRT-18G cells

Canine respiratory coronavirus (CRCoV), identified in 2003, is a member of the Coronaviridae family. The virus is a betacoronavirus and a close relative of human coronavirus OC43 and bovine coronavirus. Here, we examined entry of CRCoV into human rectal tumor cells (HRT-18G cell line) by analyzing co-localization of single virus particles with cellular markers in the presence or absence of chemical inhibitors of pathways potentially involved in virus entry. We also targeted these pathways using siRNA. The results show that the virus hijacks caveolin-dependent endocytosis to enter cells via endocytic internalization